In a conventional semiconductor wafer polishing apparatus, a wafer to be polished is held by a wafer holding plate (a carrier) of a polishing head, a surface of the wafer is brought into contact with a polishing cloth adhered on an upper face of a polishing plate, and the polishing plate and the polishing head are relatively moved with respect to each other, with supplying slurry onto the polishing cloth, so that the surface of the wafer can be polished.
In a wafer polishing apparatus disclosed in Japanese Laid-open Patent Publication No. 10-340870, dedicated polishing plates and mechanisms for different polishing processes, e.g., a polishing plate for primary polishing, a polishing plate for secondary polishing, a polishing plate for finish polishing, a wafer cleaning mechanism, are provided.
In a wafer polishing apparatus disclosed in Japanese Laid-open Patent Publication No. 9-277159 or No. 2003-305638, different polishing cloths are concentrically adhered on an inner part and an outer part of a polishing face of a polishing plate so as to continuously perform different polishing processes.
In the wafer polishing apparatus disclosed in Japanese Laid-open Patent Publication No. 10-340870, the dedicated polishing plates and mechanisms for different polishing processes are provided, so the wafer polishing apparatus must be large in size.
In the wafer polishing apparatus disclosed in Japanese Laid-open Patent Publication No. 9-277159, the different polishing cloths are concentrically adhered on one polishing plate, so different types of slurries which are used in different polishing processes will be mixed on the polishing plate. Further, in some cases, break-in times, life spans, etc. of the polishing cloths for the different processes, e.g., the primary polishing process, the finish polishing process, are extremely-different. If the polishing cloths whose characteristics are extremely-different are simultaneously used, the inner polishing cloth and the outer polishing cloth are separately exchanged. But, it is very difficult to separately exchange the polishing cloths.
In the wafer polishing apparatus disclosed in Japanese Laid-open Patent Publication No. 2003-305638, a groove is formed between polishing zones, so that mixing slurries can be prevented. However, a plurality of polishing heads, each of which corresponds to each of the polishing zones, are provided, so a structure of the wafer polishing apparatus must be complicated, and a size thereof must be large.